Apparatus for normalizing steel sheets



F. W. PITTS I APPARATUS FOR' NORMALIZING STEEL SHEETS Filed Jn.l 28. 1929 2 Sheets-Sheet 1 l S xNvENToR 15355 erft/f if /Dvzts' ATTORNEYS Oct'. 13, 1931. F w. PxTTs 1,327,038

Armwrus FoNo'RuALIzING STEEL SHEETS' Filed Jan. 28. 1929` 2 sheets-sheet 2 INVENToR y ATTORNEY;

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Patented Oct. 13; 1931 PATTI-:NT OFFICE FREDERICK W. rms, or

DETROIT, MICHIGAN, A-SSIGNOR T0 MICHIGAN STEEL COR- POB'IATION, 0F DETROIT, MICHIGAN, A CORPORATION OF NEW JERSEY` APPARATUS FOR NORMAIJZING- STEEL SHEETS I Application mea January as, 1929. serial No. 335,643.

This inventionrel'ates to a method and apparatus for normalizing or heat treating steel sheets or the like.

An object of this invention is to provide a method of theabov'e character in which the production may be considerably speedednp without in any way impairing the resulting product.

A further object of this invention is to pro- -vide a method of the above character which 'will prevent they burning or rashing of the steel sheets during their passage through the furnace and which will accordingly produce a more evenly treated sheet.

j The invention has as a further object the vat provision of a furnace having an open end into which the sheets to' be treated are introduced and having means for eliminating the cold area-normally present adjacent the open end of a furnace of this character. Other objects and advantages of the invention as well as the numerous novel details of construction will become apparent as the following description. proceeds, particularly when reference is had to the accompanying drawings wherein, p t 4 Figure 1 'is a vertical sectional view through an end of a furnace constructed'in accordance with the teachings of this invention',

Figure 2 isa horizontal sectional view taken substantially on the line 2 1-2 of Figure 1, and j r ,A

Figure 3` is a transverse sectional view taken' substantially on the line 3-3 of Figurel. v s

Figure 4 is a' sectional view taken on the line 4 -4 of Figure 1.

In the normalizing or heat treat-ing of steel sheets and the like it has been customary to convey the sheets to be treated. through'an elongated heating chamber. During the passage of the sheets through the chamber,.the sheets have. been`subjected to the action of heating gases directed toward the upper faces of the s top of the heating chamber. These burners have been arranged at spaced points longitudinally of the chamber and it has been customary to introduce the sheets into the open ing chamber.

eets from burners arranged in the,

inlet end of the chamber and to remove the sheets from the open outlet end of the chamber after the saine-have been properly heat treated.

In a furnace of this character, however, difficulty has been experienced in preventing the formation of hot spots which tend to burn -the sheets at certain points. A further difficulty has been encountered in the elimination of the cold area normally present adjacent the inlet end of the chamber. In other words, it has been found that the first fifteen or twenty feet of the heating chamber adjacent the inlet end thereof has been so cold as to be ineffective in the treating of the sheets, so that the actual heat treating or normalizing of the sheets has not been commenced until the sheets have been conveyed to a point within the heating chamber from fifteen or twenty feet from the inlet end thereof.

The present invention contemplates a method in which the sheets to be treatedfare passed through a heating chamber being introduced at the inlet end thereof and being removed from the outlet end of the chamber after they havev been properly heat treated. The invention further contemplates the provision ofv burners arranged in the upper portion of the heating chamber for directing heating gases downwardly toward the upper faces ofthe sheets as-they are conveyed through the heat- All of this is in accordance with the old practice, but' the present invention contemplates -in addition to the above steps, the step of heating the underfaces of the sheets of steel immediately after they are fed into the inlet end of the heating chamber. In particular, the present invention contemplates the provision of a method wherein hot gases are directed toward the underfaces of the sheets of steel adjacent the inlet end of the heating chamber whereby the cold area normallypresent adjacent the inlet end of the furnace of the character described is eliminated, thus making the entire length of the heating chamber effective for` the heat treating of the vsteel sheets. 7 v

While the method above 'described might be carried out in any one of a number of different'ways, there is disclosed in the drawnaar walls 11, top wall 12 and floor 13, which togather. form an elongated heating chamber esignated generally by the reference character 14. The numeral 15 designates the inlet end of the chamber 14, it Ibeing understood that the sheets 16to be heat treated are fed into the chamber 14 at 15 and are conveyed through the chamber to be discharged at the j outlet end thereof (not shown).

For conveying the sheets 16 through the heating chamber 14, there may be provided a plurality of shafts ,17 journaled at spaced olnts longitudinally of the furnace I in brackets 18, secured as at 19, to suitable uprights 20 arranged on opposite sides of the furnace. Secured to the shafts 17 are rollers 21 on which the sheets 16 are adapted to ride .and for driving the shafts 17 each shaft is "provided at its one end with a bevel gear 22 adapted to be driven from a main drive shaft 23 by a suitable gear 24. The shaft 23 extends longitudinally of the furnace adjacent one side thereof and is driven by any suitable motor (not shown). The shaft 23 will carry a plurality'of the gears 24 there being one gear for each shaft 17 so that all of the shafts 17 and the rollersl 21 carried thereby will be driven in synchronism. Thus sheets of steel fed into the open end 15 of the chamber 14 and on to the' rollers 21 will be,A conveyed longitudinallyof the heating chamber for dischar e through the discharge end thereof, as will e readily understoods- -For directing hot gases. downwardly toward the upper lfaces of the sheets 16 as they pass through the heating chamber 14, there are provided a plurality of oil burners 25 arranged at spaced 'points longitudinally of the furnace 10. These burners 25 are mounted in the side walls 11 of the furnace as clearly illustrated in Figure 3 of the drawings so that the iiames 26 issuing from the burners are directed inwardly toward the center of the heating chamber 14. In order .that the flames 26 will be directed downwardly toward the sheets 16 the inner face of the top 12 of the furnace is arched as at 27, thearchesMi being in the form of stepped surfaces adapted to deiect the iames downwardly toward the sheets 16, as will be readily apparent by reference to Figure 3 of the drawings.

The\structure of the furnace as thus far described is substantially standard'practice and forms no part of .the present inyention5 being merely illustrated for the purpose of more clearly bringing 'out the manner in V which the cold area adjacent the inlet end of pit..

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the furnace is eliminated. lt will be undef stood that in ractice the sheets 16 are fed into the chamg conveyed by the rollers 21 through the heating chamber during which time they are subjected to the hot gases deflected downwardly from the burners 25 rby the arches 27 lin actual practice itis customary to place each sheet 16 on a waste sheet 28 as clearly illustrated in the drawings in order to prevent contact of the sheets with the rollers 21. As brought out before, it has been found that in a furnace of the character above described there has been a cold area adjacent the inlet end 15 of .the furnace, this area extending from fifteen or twenty feet longitudinally of the furnace. The present invention contemplates the elimination of this cold area by the provision of burners located adjacent the inlet end 15 ofthe furnace, these burners being adapted to direct heating gases toward the underfaces of the sheets 16 during the initial portion of their passage through the furnace.

v Referring then particularly to Figures t1 and 2 of the drawings, it^will be noted that er 14 from the end 15, being there is provided a pit 3() arranged adjacent the end 15 of the furnace. The pit 30 is *ar-c ranged Ibelow the furnace and communicates directly with the heating chamber thereof,

. the Hoor 15l being cut away topermit this communication as will be readily apparent by reference to Figure 1. The pit 30 extends entirely across the furnace 10 and is provided with the rearward extension 31 communicating with a lateral extension 32 which extends outwardly beyond the side of the furnace, whereby access may be had to the pit 30 from the side-of the furnace. There may be p rovided a ladder 33 in the extension 32 of the 'pit so that an attendant may conveniently enter the extension 32 of the pit land walk from this extension to the pit proper` designated generally by the reference character 30.

The pit 30 is provided at its upper forward l end with an extension 35 which extends longitudinally of the heating chamber 14 in the direction of travel of the sheets. This extension is below the rollers 21 and is proj oil burners or the like 38 havingrtheir nozzles directed inwardly toward the recess 35.

The hot gases and products of combustion from the burners 38` are directed upwardly by the steppedior arched ioor of the recess and between the rollers 21 to heat the sheets'16 passing through the furnace. Each burner may be provided w'ith a suitable valve 39 arranged within the pit 30 whereby the burners may be conveniently controlled from the said From the above it is believed that the structure'and operation of the furnace will be readily apparent. In use, the sheets 16 superposed on the waste sheets 28 are fed into the heating chamber at the inlet end thereof. These sheets are'carried throughl the furnace by the rollers 21 and are heated from above by the products of combustion from the burners 25 deflected downwardly by the arches 27. 'Adjacent the inlet end 15 ofthe furnace the burners 38 are provided, the products of combustion of which are projected into the recess 35 from which they are deiected upwardly toward the sheets 16. Thus that portion of the furnace adjacent the inlet end thereof will be heated and the cold area normally found adjacent the inlet end will be eliminated, making more effective this portion of the furnace. The pit 30 being accessible from the side of the furnace forms a convenient place from which the attendant may control the burners 38 to regulate the heat at the inlet end of the furnace in order that burning or rashing 0f the sheets will be prevented.

While one method and one apparatus has been described with considerable detail, it is to be clearly understood that the description is for the purposes of illustration only. The right is therefore reserved to make such changes in the details of construction and arrangement of parts as will fall within the purview of the attached claims.

What I claim as my invention is:

1. A furnace for normalizing articles including in combination an elongated chamber having a charge receiving end portion, means in said chamber for conveying the articles from the charge receiving end portion aforesaid longitudinally of. the, chamber means arranged at longitudinally spaced points upon opposite sides of the chamber and adjacent the upper portions thereof for effecting combustion in the chamber above the articles,passing therethrough, a baffle extending longitudinally of the chamber and projecting downwardly from the top wall thereof into the path of the products of combustion discharged by said last mentioned means for deflecting the heatinggases downwardly toward the articles passing through the furnace, a pit arranged below the chamber adjacent the charge receiving end thereof and having a portion extending longitudinally of the chamber in the direction of travel of said articles, said portion terminating at the inner end thereof in an upwardly extending tapered wall forming a baflie, and means for effecting combustion in the extension aforesaid operable to impinge the products of combustion against said baiiie whereby the heating gases are deected upwardly toward the articles passing through the furnace.

2. In a furnace'for normalizing a sheet of steel including in combination an elongated open-ended heatin chamber, means arranged at longitudlnally spaced points adjacent the up er portion of the chamber for effecting com ustion therein above the a rticles passing therethrough, a baliie extending longitudinall of the chamber and positioned in the path o the products of combustion for deflecting the same downwardly toward the uppersurface of the articles passing through the furnace, a second chamber arranged below the first mentioned chamber in communication therewith and extending longitudinally thereof, means positioned in one end wall of the second mentioned chamber for effecting combustion in the direction of the move-y ment of the articles and the opposite end wall fashioned for deecting the products of combustion u wardly toward the under surface of the artlcles.

In testimony whereof I aix my signature.

FREDERICK W. PITTS. 

